/**
  * 获取文章内容表的dao实例
  * @param int $aid 文章ID
  * @return \herosphp\model\C_Model
  */
 public function getDataDao($aid)
 {
     //获取文章数据表的节点
     $node = $aid % self::DATA_TABLE_NODES;
     $this->dataDao = Loader::model('ArticleData');
     $tableMapping = $this->dataDao->getTableMapping();
     //加载数据表配置
     $dbConfigPath = 'db';
     if (DB_CFG_PATH != false) {
         $dbConfigPath = DB_CFG_PATH;
     }
     $tableConfig = Loader::config('table', $dbConfigPath);
     $this->dataDao->setTable($tableConfig[$tableMapping[$node]]);
     return $this->dataDao;
 }